1. Field of the Invention
The present invention relates to a library device that performs recording/reproduction of data by automatically feeding a recording medium such as a magnetic tape to a recording/reproducing device (drive), and more particularly to a library device that can enhance stop precision by using a feeding mechanism that feeds the recording medium to a housing cabinet.
2. Description of the Related Art
Recently, due to a large amount of data in a computer system or for searching data such as multimedia, graphic data etc. that necessitates a large storage capacity, a library device that includes a recording cartridge type-recording medium that records data is increasingly necessitated. The library device includes a function that automatically attaches a magnetic tape cartridge to a cell, removes the magnetic tape cartridge from the cell, and performs storage, recording/reproduction of data etc. in the magnetic tape cartridge.
To be specific, the library device internally includes a medium-handling robot (a feeding mechanism) called accessor. The accessor automatically performs insertion of the recording medium in a medium housing cabinet (cell) and removal of the recording medium from the medium housing cabinet. Similarly, the accessor automatically performs mounting of the recording medium on the medium housing cabinet and a recording/reproducing device (Magnetic Tape Unit (MTU)/drive) and demounting of the recording medium from the medium housing cabinet and the recording/reproducing device. Further, the library device is communicably connected to a host computer. Based on an instruction from the host computer, the library device automatically performs storage, recording/reproduction of data etc. on the magnetic tape cartridge.
A technology is disclosed (for example, see Japanese Patent Application Laid-open No. H7-85562) which relates to the library device that feeds the recording medium such as the magnetic tape cartridge to a predetermined position in the housing cabinet and performs recording/reproduction of data using the recording/reproducing device. Further, the present inventor has prior predicted occurrence of a failure in the feeding mechanism and has disclosed a technology in which an auxiliary feeding mechanism is included separately from a main feeding mechanism and the auxiliary feeding mechanism is used to feed the recording medium when a failure occurs in the main feeding mechanism (see Japanese Patent Application No. 2004-220813).
However, the commonly used library device mentioned earlier includes the following drawbacks. In other words, in the commonly used library device, due to life span of a feeding motor or occurrence of a failure in the feeding motor that actually moves the feeding mechanism, a stop precision of the feeding mechanism worsens and a large scale failure is likely to result in the feeding mechanism being overdriven, thereby damaging the recording medium that is being fed or that is housed. Further, when using the library device that includes the main feeding mechanism and the auxiliary feeding mechanism, mounting efficiency of the recording medium is enhanced, thereby resulting in occurrence of a plurality of movable stop positions and further necessitating the stop precision at the movable stop positions.
The drawbacks mentioned earlier are explained based on an overview of the commonly used feeding mechanism. FIG. 31 is a perspective view of the commonly used feeding mechanism. In other words, as shown in FIG. 31, a feeding mechanism 50 includes a swivel mechanical unit 51, a tilt mechanism 52, a Z-axis mechanical unit 53, a hand mechanical unit 54, and holding pawls 55. The swivel mechanical unit 51 controls a direction of the feeding mechanism 50 at a predetermined inclination angle. The tilt mechanism 52 controls a movement of the feeding mechanism 50 in a vertical direction. The Z-axis mechanical unit 53 controls a movement direction of the feeding mechanism 50. The hand mechanical unit 54 uses the holding pawls 55 to hold the magnetic tape cartridge. Further, if the feeding mechanism 50 is overdriven, a stopper member 56 stops the movement of the feeding mechanism 50.
In other words, in the feeding mechanism 50 that is commonly used, a range of movement (stroke) in a movement stroke of the feeding mechanism 50 differs according to the inclination angle of the feeding mechanism 50. Further, when moving the feeding mechanism 50, a clearance between the feeding mechanism 50 and magnetic-tape housing cabinets 220 (shown in FIG. 3) is negligible. Due to this, the recording medium, which is being fed by the feeding mechanism 50 or is stored in the housing cabinets 220, is likely to be damaged.
To be specific, when a direction of the feeding mechanism 50 is 90 degrees (or −90 degrees in the opposite direction) and the feeding mechanism 50 moves (accesses) towards the housing cabinets 220 that are positioned either to the left or to the right, the movement stroke of the feeding mechanism 50 is approximately 103 millimeters (mm). Thus, the clearance between the feeding mechanism 50 and the housing cabinets 220 is negligible (approximately 11.5 mm).
Due to this, if a failure occurs during the movement of the feeding mechanism 50, the feeding mechanism 50 and the housing cabinets 220 are likely to come closer and touch each other. Moreover, when accessing a cabinet that is positioned at a top portion of a recording/reproducing device 230 in the direction of the recording/reproducing device 230 (a position of the feeding mechanism 50 is 0 degree), the movement stroke of the feeding mechanism 50 is approximately 113.4 mm. Thus, the clearance between the feeding mechanism 50 and the cabinets that are positioned either to the left or to the right is negligible (approximately 10 mm). Thus, the recording medium is likely to be damaged due to touching of the feeding mechanism 50 and the housing cabinets 220.